Because high-availability and fault-tolerant systems need strong security

Recent studies have shown that hackers (both internal and external) often use relatively simple attack methods and that it’s as important as ever to follow basic security best practices. Therefore, it makes sense that the first three items in our Top 10 list were about establishing a base level of security within the NonStop system:

#10 Secure the default system access settings
#9 Set-up strong Safeguard authentication and password controls
#8 Ensure individual accountability (no shared IDs!)


Now that we’ve covered those broader fundamentals, this week we’ll get into a more “granular” security topic—controlling user activity at different levels within the NonStop system.
#7: Establish granular control of user activity

A fundamental IT security challenge is to provide users with only the system access and privileges they need to do their jobs (least privilege or Role Based Access Control RBAC).  Allowing users to have system access and privileges greater than their job requires presents a significant security risk—particularly on the NonStop which typically has mission critical applications running and sensitive information being processed or stored.  The risk is not only from intentionally malicious activity but also from the possibility of an unsophisticated (or stressed or rushed) user, when given too much power, not realizing the ramifications of their actions.


So, to protect the NonStop, it’s important to establish more granular control of what users can do within multiple areas within the system.  Let’s specifically look at four areas: user, process, CMON, and spooler.


User. The system access a user may have, and actions a user may take, are determined by their identity and their membership in predefined groups. When a user attempts to access an object, Safeguard checks the object’s Access Control List (ACL) to either grant or deny specific access privileges to the underlying object. Third-party solutions are available to improve the NonStop’s access management and increase the granularity of control (to the sub-command level, for instance). For example, XYGATE Access Control (XAC) acts as a sentry between users and programs or utilities and, based on configuration settings defined in XAC’s Access Control List (ACACL), user requests to programs or utilities are granted or denied. Furthermore, XAC’s “allow” and “deny” features restrict commands within programs and utilities to the sub-command level for separation of duties and efficient job performance. An example of this would be giving a user privileged access to FUP running as SUPER.SUPER in order to perform their job duties but specifically denying any use of the LICENSE command.


Process. Processes are a type of Safeguard object and, obviously, they need to be managed closely. As with the “User” area discussed above, Safeguard manages access to processes with ACLs. Again, third party solutions can assist with process security and management; XYGATE Process Control (XPC) behaves similarly to XAC in that it sits between the user and the process they wish to manage. The difference lies in that the object is a process and privileges such as the ability to stop, suspend, alter priority, activate and debug the process can be granted to the user ID, whether or not they are the owner of that process. The benefit of this is that if the owner of a process is not present and an action must be taken for the good of the system (stop a runaway process for example), other authorized users can take these actions under their own logon, without having to share userids.


$CMON. The NonStop server has an interface to a user-supplied Command Monitoring Process named $CMON. While the $CMON program is not HP-supplied, it’s recommended that every NonStop system use a $CMON either written by the customer or supplied by a third-party (such as the XYGATE supported $CMON module). When a $CMON is present, messages are sent to the $CMON to verify logon requests and process start requests. The $CMON process can provide many functions for both security and performance reasons:

  • Control the CPU and the priority of the request
  • Control who can logon to a specific ports
  • Verify a userid’s request to run a requested program
  • Audit the request
  • Ensure that the location and priority of all processes is only controlled via $CMON


Note that not having a $CMON presents a serious risk because, if a $CMON is not present, an unauthorized $CMON could be added to the system.  The unauthorized $CMON might be used simply to monitor the system or it could be designed with malicious intent (such as stopping, denying or slowing services).

Spooler.   The HPE NonStop server spooler subsystem is a set of utilities that provides an interface to the system’s print facilities.  The spooler receives output from applications and stores it on disk where it can be viewed or sent to a print location for printing.  Clearly, access to the spooler needs to be managed to protect sensitive data on disk and to keep it from being printed (print outs being one way to extract stolen data).  Furthermore, users with PERUSE access to a job can access the job output’s contents.  To protect this area, limit access to spooler utilities to only those users requiring it for their job function.  Third-party solutions, such as XYGATE Spoolcom Peruse (XSP), are available to improve security of the spooler, simplify task management and administration and allow for delegation of authority.


So that’s #7: Establish granular control of user activity. Increasing the granularity of control builds on security concepts discussed in earlier blog posts and goes deeper into specific system areas which need closer security management.


For more information or help: More in-depth information and guidance on these security subjects are available in XYPRO’s NonStop security handbooks: HPE NonStop Server Security: A Practical Handbook and Securing HPE NonStop Servers in an Open Systems World: TCP/IP, OSS and SQL. PCI information can be found at:


You may also contact XYPRO for assistance. For over 30 years, XYPRO has provided NonStop security solutions and services that help companies protect their NonStop systems and comply with industry regulations (such as PCI DSS, HIPAA, and SOX).